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Evaluating and Implementing JPEG XR Optimized for Video SurveillanceYu, Lang January 2010 (has links)
This report describes both evaluation and implementation of the new coming image compression standard JPEG XR. The intention is to determine if JPEG XR is an appropriate standard for IP based video surveillance purposes. Video surveillance, especially IP based video surveillance, currently has an increasing role in the security market. To be a good standard for surveillance, the video stream generated by the camera is required to be low bit-rate, low latency on the network and at the same time keep a high dynamic display range. The thesis start with a deep insightful study of JPEG XR encoding standard. Since the standard could have different settings,optimized settings are applied to JPEG XR encoder to fit the requirement of network video surveillance. Then, a comparative evaluation of the JPEG XR versusthe JPEG is delivered both in terms of objective and subjective way. Later, part of the JPEG XR encoder is implemented in hardware as an accelerator for further evaluation. SystemVerilog is the coding language. TSMC 40nm process library and Synopsys ASIC tool chain are used for synthesize. The throughput, area, power ofthe encoder are given and analyzed. Finally, the system integration of the JPEGXR hardware encoder to Axis ARTPEC-X SoC platform is discussed.
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Evaluation of Word Length Effects on Multistandard Soft Decision Viterbi DecodingSalim, Ahmed January 2011 (has links)
There have been proposals of many parity inducing techniques like Forward ErrorCorrection (FEC) which try to cope the problem of channel induced errors to alarge extent if not completely eradicate. The convolutional codes have been widelyidentified to be very efficient among the known channel coding techniques. Theprocess of decoding the convolutionally encoded data stream at the receiving nodecan be quite complex, time consuming and memory inefficient.This thesis outlines the implementation of multistandard soft decision viterbidecoder and word length effects on it. Classic Viterbi algorithm and its variantsoft decision viterbi algorithm, Zero-tail termination and Tail-Biting terminationfor the trellis are discussed. For the final implementation in C language, the "Zero-Tail Termination" approach with soft decision Viterbi decoding is adopted. Thismemory efficient implementation approach is flexible for any code rate and anyconstraint length.The results obtained are compared with MATLAB reference decoder. Simulationresults have been provided which show the performance of the decoderand reveal the interesting trade-off of finite word length with system performance.Such investigation can be very beneficial for the hardware design of communicationsystems. This is of high interest for Viterbi algorithm as convolutional codes havebeen selected in several famous standards like WiMAX, EDGE, IEEE 802.11a,GPRS, WCDMA, GSM, CDMA 2000 and 3GPP-LTE.
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Vektorkvantisering för kodning och brusreducering / Vector quantization for coding and noise reductionCronvall, Per January 2004 (has links)
This thesis explores the possibilities of avoiding the issues generally associated with compression of noisy imagery, through the usage of vector quantization. By utilizing the learning aspects of vector quantization, image processing operations such as noise reduction could be implemented in a straightforward way. Several techniques are presented and evaluated. A direct comparison shows that for noisy imagery, vector quantization, in spite of it's simplicity, has clear advantages over MPEG-4 encoding.
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Studies on the effects of low-field Landau quantization in a two-dimensional electron systemZhang, Yan-wei 21 July 2005 (has links)
In this paper, we mainly discuss the transport properties of the two-dimensional gas of a high-mobility GaAs/AlGaAs semiconductor heterostructure in high magnetic fields and low temperatures. We analyzed the measured longitudinal resistivity and Hall resistivity at the five different temperatures. We observed that the classical Hall effect is valid when the magnetic field is less than 0.25 Tesla; and the quantum Hall plateaux appeared obviously when the magnetic field is larger than 1.6 Tesla. We proceeded to analyze the longitudinal resistivity oscillation occurred in the magnetic fields between 0.477 Tesla and 1.483 Tesla. According to the Lifshitz-Kosevich (LK) formula, we can get the two-dimensional electron concentration, effective mass, and quantum scattering time from the quantum magnetoresistivity oscillation measurement. Our results suggested that the applicable range of the LK formula could be broader than the generally-assumed one. In quantum Hall effect regime at high magnetic field, we can calculate the h/e2 value from the quantum Hall plateaux value.
In classical Hall effect regime, the three-dimensional electron concentration and classical mobility (classical scattering time) can be obtained. However, we find out that the zero-field Hall resistivity experimental value is not equal to zero, and this is not conformed to the standard theory. We tried to use the magnetic field shift and Hall resistivity shift to solve the problem, and compared both advantages of them.
Finally, we observed the plateau-plateau phase transitions of the two-dimensional electron system
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An Improved C-Fuzzy Decision Tree and its Application to Vector QuantizationChiu, Hsin-Wei 27 July 2006 (has links)
In the last one hundred years, the mankind has invented a lot of convenient tools for pursuing beautiful and comfortable living environment. Computer is one of the most important inventions, and its operation ability is incomparable with the mankind. Because computer can deal with a large amount of data fast and accurately, people use this advantage to imitate human thinking. Artificial intelligence is developed extensively. Methods, such as all kinds of neural networks, data mining, fuzzy logic, etc., apply to each side fields (ex: fingerprint distinguishing, image compressing, antennal designing, etc.). We will probe into to prediction technology according to the decision tree and fuzzy clustering. The fuzzy decision tree proposed the classification method by using fuzzy clustering method, and then construct out the decision tree to predict for data. However, in the distance function, the impact of the target space was proportional inversely. This situation could make problems in some dataset. Besides, the output model of each leaf node represented by a constant restricts the representation capability about the data distribution in the node. We propose a more reasonable definition of the distance function by considering both input and target differences with weighting factor. We also extend the output model of each leaf node to a local linear model and estimate the model parameters with a recursive SVD-based least squares estimator. Experimental results have shown that our improved version produces higher recognition rates and smaller mean square errors for classification and regression problems, respectively.
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Cluster Based User Scheduling Schemes To Exploit Multiuser Diversity In Wireless Broadcast ChannelsSoydan, Yusuf 01 September 2008 (has links) (PDF)
Diversity methods are used to improve the reliability of the communication between
transmitter and receiver. These methods use redundancy to reduce the errors in the
communication link. Apart from the conventional diversity methods, multiuser
diversity has an aim of maximizing the sum capacity of a multi-user system. To
benefit from multiuser diversity, the opportunistic scheduling method grants the
channel access to the user which has the best channel quality among all users.
Therefore, the cumulative sum of the information sent to all users, which is the sum
capacity, is maximized in the long term.
Although the opportunistic scheduling maximizes the sum capacity, it has some
drawbacks such as the feedback load growing with the number of users and the
problem of fairness for the users which may have lower channel quality than some
other users. In this thesis, these two issues are investigated for the broadcast channels.
Feedback quantization, which gives partial information on the channel state, is
studied to mitigate the feedback load with a goal of little loss in the sum capacity.
The thresholds for the finite feedback quantization are determined to provide fairness and to reduce the feedback load at the same time. To provide fairness, users are
grouped into clusters and thresholds are optimized for each cluster. A method is
proposed by extending the one given by Floren et. al. to solve the mentioned
problems and the proposed method is compared with some other scheduling methods
in the literature.
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Hardware Implementation Of Inverse Transform & / Quantization And Deblocking Filter For Low Power H.264 DecoderOnsay, Onder 01 September 2009 (has links) (PDF)
Mobile devices such as PDAs and cellular phones became indispensible part of business and entertainment world. There are a number of applications run on these devices and they tend to increase day by day causing devices tend to consume more battery power. H.264/AVC is an emerging video compression standard that is likely to be used widely in multimedia environments. As a mobile application, video compression algorithm of H.264 standard has a complex structure that increase the power demand of realizing hardware. In order to reduce this power demand, power consuming parts of the algorithm like deblocking filter and transform& / quantization need to be specifically changed for low power application. A low power deblocking filter and inverse transform/quantization algorithm for H.264/AVC decoder is to be proposed and implemented on FPGA.
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Direct dynamical tunneling in systems with a mixed phase spaceSchilling, Lars 19 July 2007 (has links) (PDF)
Tunneling in 1D describes the effect that quantum particles can penetrate a classically insurmountable potential energy barrier. The extension to classically forbidden transitions in phase space generalizes the tunneling concept. A typical 1D Hamiltonian system has a mixed phase space. It contains regions of regular and chaotic dynamics, the so-called regular islands and the chaotic sea. These different phase space components are classically separated by dynamically generated barriers. Quantum mechanically they are, however, connected by dynamical tunneling. We perform a semiclassical quantization of almost resonance-free regular islands and transporting island chains of quantum maps. This yields so-called quasimodes, which are used for the investigation of direct dynamical tunneling from an almost resonance-free regular island to the chaotic sea. We derive a formula which allows for the determination of dynamical tunneling rates. Good agreement between this analytical prediction and numerical results is found over several orders of magnitude for two example systems. / Der 1D Tunneleffekt bezeichnet das Durchdringen einer klassisch nicht überwindbaren potentiellen Energiebarriere durch Quantenteilchen. Eine Verallgemeinerung des Tunnelbegriffs ist die Erweiterung auf jegliche Art von klassisch verbotenen Übergangsprozessen im Phasenraum. Der Phasenraum eines typischen 1D Hamiltonschen Systems ist gemischt. Er besteht aus Bereichen regulärer und chaotischer Dynamik, den sogenannten regulären Inseln und der chaotischen See. Während diese verschiedenen Phasenraumbereiche klassisch durch dynamisch generierte Barrieren voneinander getrennt sind, existiert quantenmechanisch jedoch eine Verknüpfung durch den dynamischen Tunnelprozess. In dieser Arbeit wird eine semiklassische Quantisierung von praktisch resonanz-freien regulären Inseln und transportierenden Inselketten von Quantenabbildungen durchgeführt. Die daraus folgenden sogenannten Quasimoden werden für die Untersuchung des direkten dynamischen Tunnelns aus einer praktisch resonanz-freien regulären Insel in die chaotische See verwendet, was auf eine Tunnelraten vorhersagende Formel führt. Ihre anschlie?ßende Anwendung auf zwei Modellsysteme zeigt eine gute Übereinstimmung zwischen Numerik und analytischer Vorhersage über viele Größenordnungen.
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Quantized Feedback for Slow Fading ChannelsKim, Thanh Tùng January 2006 (has links)
<p>Two topics in fading channels with a strict delay constraint and a resolution-constrained feedback link are treated in this thesis.</p><p>First, a multi-layer variable-rate single-antenna communication system with quantized feedback, where the expected rate is chosen as the performance measure, is studied under both short-term and long-term power constraints. Iterative algorithms exploiting results in the literature of parallel broadcast channels are developed to design the system parameters. A necessary and sufficient condition for single-layer coding to be optimal is derived. In contrast to the ergodic case, it is shown that a few bits of feedback information can improve the expected rate dramatically. The role of multi-layer coding, however, reduces quickly as the resolution of the feedback link increases.</p><p>The other part of the thesis deals with partial power control systems utilizing quantized feedback to minimize outage probability, with an emphasis on the diversity-multiplexing tradeoff. An index mapping with circular structure is shown to be optimal and the design is facilitated with a justified Gaussian approximation. The diversity gain as a function of the feedback resolution is analyzed. The results are then extended to characterize the entire diversity-multiplexing tradeoff curve of multiple-antenna channels with resolution-constrained feedback. Adaptive-rate communication is also studied, where the concept of minimum multiplexing gain is introduced. It is shown that the diversity gain of a system increases significantly even with coarsely quantized feedback, especially at low multiplexing gains.</p>
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Imperfect Channel Knowledge for Interference AvoidanceLajevardi, Saina Unknown Date
No description available.
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